<template>
	<view>
		<view class="search-box">
			<!-- cancelButton: none 使得右侧的取消按钮永不显示 -->
			<uni-search-bar @input="input" :radius="100" :cancelButton="'none'" :focus="true" />
		</view>
		
		<!-- 搜索建议列表 -->
		<view class="sugg-list" v-if="searchResults.length !== 0">
			<view class="sugg-item" v-for="(item, index) in searchResults" :key="index" @click="gotoDetail(item.goods_id)">
				<view class="goods-name">{{ item.goods_name }}</view>
				<uni-icons type="arrowright" size="16"></uni-icons>
			</view>
		</view>
		
		<!-- 搜索历史 -->
		<view class="history-box" v-else>
			<!-- 标题区域 -->
			<view class="history-title">
				<text>搜索历史</text>
				<uni-icons type="trash" size="17" @click="cleanHistory"></uni-icons>
			</view>
			<!-- 列表区域 -->
			<view class="history-list">
				<uni-tag v-for="(item, index) in histories" :text="item" :key="index" @click="gotoGoodsList(item)"></uni-tag>
			</view>
		</view>
	</view>
</template>

<script>
	export default {
		data() {
			return {
				// 延时器的timerId
				timer: null,
				// 搜索关键词
				kw: '',
				// 搜索建议列表
				searchResults: [],
				// 搜索关键词的历史记录
				historyList: []
			};
		},
		computed: {
			histories () {
				// 这么做的原因：reverse会修改原数组
				return [...this.historyList].reverse()
			}
		},
		methods: {
			// input输入事件的处理函数
			input (value) {
				clearTimeout(this.timer)
				this.timer = setTimeout(() => {
					this.kw = value
					this.getSearchList()
				}, 500)
			},
			async getSearchList () {
				if (this.kw.length === 0 || this.kw === '') {
					this.searchResults = []
					return
				}
				// 发起请求，获取搜索建议列表
				const {data: res} = await uni.$http.get('/api/public/v1/goods/qsearch', { query: this.kw })
				if (res.meta.status !== 200) return uni.$showMsg()
				this.searchResults = res.message
				
				this.saveSearchHistory()
			},
			gotoDetail (goods_id) {
				uni.navigateTo({
					url: '/subpkg/goods_detail/goods_detail?goods_id=' + goods_id
				})
			},
			// 保存搜索关键词
			saveSearchHistory () {
				// this.historyList.push(this.kw)
				
				// 1. 将Array数组转化成set对象
				const set = new Set(this.historyList)
				// 2. 调用set对象的delete方法，移除对应的元素
				set.delete(this.kw)
				// 3. 调用set对象的add方法，向set中添加元素
				set.add(this.kw)
				// 4. 将set对象转化为array数组
				this.historyList = Array.from(set)
				// 调用 uni.setStorageSync(key, value) 将搜索历史记录持久化存储到本地
				uni.setStorageSync('kw', JSON.stringify(this.historyList))
			},
			// 清空搜索历史记录
			cleanHistory () {
				this.historyList = []
				uni.setStorageSync('kw', '[]')
			},
			// 跳转到商品列表页面
			gotoGoodsList (item) {
				uni.navigateTo({
					url: '/subpkg/goods_list/goods_list?query=' + item
				})
			}
		},
		onLoad() {
			this.historyList = JSON.parse(uni.getStorageSync('kw') || '[]')
		}
	}
</script>

<style lang="scss">
.search-box {
	// 吸顶效果
	position: sticky;
	top: 0;
	z-index: 999;
}
.sugg-list {
	padding: 0 5px;
	.sugg-item {
		display: flex;
		align-items: center;
		justify-content: space-between;
		font-size: 12px;
		padding: 13px 0;
		border-bottom: 1px solid #efefef;
		.goods-name {
			// 文字不允许换行：单行文本
			white-space: nowrap;
			// 溢出部分隐藏
			overflow: hidden;
			// 文本溢出，使用 ... 代替
			text-overflow: ellipsis;
			margin-right: 3px;
		}
	}
}

.history-box {
	padding: 0 5px;
	.history-title {
		display: flex;
		justify-content: space-between;
		height: 40px;
		align-items: center;
		font-size: 13px;
		border-bottom: 1px solid #efefef;
	}
	.history-list {
		display: flex;
		flex-wrap: wrap;
		.uni-tag {
			margin-top: 5px;
			margin-right: 5px;
		}
	}
}
</style>
